Cardiovascular disease and its associated maladies, dysfunctions and complications are a principal cause of disability and the chief cause of death in the United States. One factor contributing to cardiovascular disease is atherosclerosis. Atherosclerosis has been generally recognized as the leading health care problem both with respect to mortality and health care costs.
Atherosclerosis is a disease characterized by the deposition of fatty substances, primarily cholesterol, and subsequent fibrosis in the inner layer of an artery, resulting in plaque deposition on the inner surface of the arterial wall and degeneration. If allowed to progress, atherosclerosis can cause narrowing and obstruction of the lumen of the artery resulting in diminished or occluded blood flow. This can lead to ischemia or infarction of the predominantly affected organ or anatomical region, such as the brain, heart, intestine, or extremities.
Angiogenesis is the process of new blood vessel development from preexisting vasculature. Angiogenesis is a normal process in growth and development, as well as in wound healing. It can occur during coronary artery disease, peripheral artery disease and stroke when there is insufficient blood supply and oxygen to the tissues. Vasculogenesis is the process of blood vessel formation from endothelial progenitor cells (EPC) that differentiate in situ.
Until recently, vasculogenesis was thought to be limited to embryologic development. However, the discovery of circulating endothelial progenitor cells has provided evidence that postnatal vasculogenesis also occurs in adults. Progenitor cell-based regenerative strategies offer new perspectives in cell therapies and tissue engineering for achieving an effective revascularization of ischemic or injured tissues. Cultures from peripheral blood contain cells termed early-EPC that share some endothelial but also monocytic characteristics and exhibit a restricted capacity of expansion. Another cell population isolated from peripheral blood cultures is called late-EPC or blood outgrowth endothelial cells (BOEC) that have a cobblestone morphology and have high proliferative capacity.